A wide variety of graphic articles are used for a number of different purposes including to provide information, for advertising and for decoration. Often the graphic articles include a film or multiple layers of film and an adhesive layer to adhere the graphic article to a substrate. Some or all of these layers of film may contain images, such as printed images, to generate the graphic pattern or design. If the printed portion of the graphic is on the external surface of the graphic article, it is exposed to the environment, whether the environment is indoors or outdoors, and is vulnerable to staining, graffiti, and other forms of damage.
To protect the printed images on graphic articles a variety of different techniques have been developed. One technique is to place the printed surface on an interior rather than an exterior surface. This can be achieved, for example, by printing the graphic design onto a backing film and overlaying the printed layer with an adhesive layer. In this way, when the graphic article is attached to a substrate, the printed surface is not exposed to the external environment. There are drawbacks to this technique, however. The backing film must be very optically transparent to permit clear viewing of the printed surface. Additionally, coating of the adhesive layer over the printed surface can be a time consuming and labor intensive operation unsuitable for many uses and may required specialized equipment unavailable to small scale users. For example, the advances in digital printing technology has permitted a wide variety of users to be able to print customized images onto graphic films with a relatively low capital outlay for equipment. Adhesive coaters, however, are much more labor and capital intensive.
Another method of generating a graphic article in which the printed image or design is protected, is to place a protective layer over the graphic article. This protective layer can be a coating, a substrate, or a film. When it is a film it is sometimes referred to as an overlaminate film. The use of coatings may be impractical in many instances because placing a coating onto a printed surface can be a time consuming and labor intensive operation unsuitable for many uses and may required specialized equipment unavailable to small scale users. Similarly, the use of substrates such as glass or plastic plates or sheets, may be impractical or even impossible. For example, if the graphic needs to be flexible enough to bend (if used on the surface of a vehicle for example), covering the graphic with a substrate is not possible. The use of overlays can provide protection to a graphic image without the bulk and rigidity of a substrate layer.